Electronics have been incorporated into many portable devices such as computers, mobile phones, tracking systems, scanners, and the like. One drawback to portable devices is the need to include the power supply with the device. Portable devices typically use batteries as power supplies. Batteries must have sufficient capacity to power the device for at least the length of time the device is in use. Sufficient battery capacity can result in a power supply that is quite heavy and/or large compared to the rest of the device. Accordingly, smaller and lighter batteries (i.e., power supplies) with sufficient energy storage are desired. Other energy storage devices, such as supercapacitors, and energy conversion devices, such as photovoltaics and fuel cells, are alternatives to batteries for use as power supplies in portable electronics and non-portable electrical applications.
Another drawback of conventional batteries is the fact that some are fabricated from potentially toxic materials that may leak and be subject to governmental regulation. Accordingly, it is desired to provide an electrical power source that is safe, solid-state and rechargeable over many charge/discharge life cycles.
One type of an energy-storage device is a solid-state, thin-film battery. Examples of thin-film batteries are described in U.S. Pat. Nos. 5,314,765; 5,338,625; 5,445,906; 5,512,147; 5,561,004; 5,567,210; 5,569,520; 5,597,660; 5,612,152; 5,654,084; and 5,705,293, each of which is herein incorporated by reference. U.S. Pat. No. 5,338,625 describes a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or first integrated power source for electronic devices. U.S. Pat. No. 5,445,906 describes a method and system for manufacturing a thin-film battery structure formed with the method that utilizes a plurality of deposition stations at which thin battery component films are built up in sequence upon a web-like substrate as the substrate is automatically moved through the stations.
U.S. Pat. No. 6,805,998 entitled “METHOD AND APPARATUS FOR INTEGRATED BATTERY DEVICES” (which is incorporated herein by reference) issued Oct. 19, 2004, by Mark L. Jenson and Jody J. Klaassen (the inventor of the present application), and is assigned to the assignee of the present invention, described a high-speed low-temperature method for depositing thin-film lithium batteries onto a polymer web moving through a series of deposition stations.
K. M. Abraham and Z. Jiang, (as described in U.S. Pat. No. 5,510,209, which is incorporated herein by reference) demonstrated a cell with a non-aqueous polymer separator consisting of a film of polyacrylonitrile swollen with a propylene carbonate/ethylene carbonate/LiPF6 electrolyte solution. This organic electrolyte membrane was sandwiched between a lithium metal foil anode and a carbon composite cathode to form the lithium-air cell. The utilization of the organic electrolyte allowed good performance of the cell in an oxygen or dry air atmosphere.
As used herein, the anode of the battery is the positive electrode (which is the anode during battery discharge) and the cathode of the battery is the negative electrode (which is the cathode during battery discharge). (During a charge operation, the positive electrode is the cathode and the negative electrode is the anode, but the anode-cathode terminology herein reflects the discharge portion of the cycle.)
U.S. Pat. No. 6,605,237 entitled “Polyphosphazenes as gel polymer electrolytes” (which is incorporated herein by reference), issued to Allcock, et al. on Aug. 12, 2003, and describes co-substituted linear polyphosphazene polymers that could be useful in gel polymer electrolytes, and which have an ion conductivity at room temperature of at least about 10−5 S/cm and comprising (i) a polyphosphazene having controlled ratios of side chains that promote ionic conductivity and hydrophobic, non-conductive side chains that promote mechanical stability, (ii) a small molecule additive, such as propylene carbonate, that influences the ionic conductivity and physical properties of the gel polymer electrolytes, and (iii) a metal salt, such as lithium trifluoromethanesulfonate, that influences the ionic conductivity of the gel polymer electrolytes, and methods of preparing the polyphosphazene polymers and the gel polymer electrolytes. Allcock et al. discuss a system that has been studied extensively for solid-polymer electrolyte (SPE) applications, which is one that is based on poly(organophosphazenes). This class of polymers has yielded excellent candidates for use in SPEs due to the inherent flexibility of the phosphorus-nitrogen backbone and the ease of side group modification via macromolecular substitution-type syntheses. The first poly(organophosphazene) to be used in a phosphazene SPE (solid polymer electrolyte) was poly[bis(2-(2′-methoxyethoxy ethoxy)phosphazene] (hereinafter, MEEP). This polymer was developed in 1983 by Shriver, Allcock and their coworkers (Blonsky, P. M., et al, Journal of the American Chemical Society, 106, 6854 (1983)) and is illustrated in U.S. Pat. No. 6,605,237.
Also, the following U.S. Pat. No. 7,052,805 (Polymer electrolyte having acidic, basic and elastomeric subunits, published/issued on May 30, 2006); U.S. Pat. No. 6,783,897 (Crosslinking agent and crosslinkable solid polymer electrolyte using the same, Aug. 31, 2004); U.S. Pat. No. 6,727,024 (Polyalkylene oxide polymer composition for solid polymer electrolytes, Apr. 27, 2004); U.S. Pat. No. 6,392,008 (Polyphosphazene polymers, May 21, 2002); U.S. Pat. No. 6,369,159 (Antistatic plastic materials containing epihalohydrin polymers, Apr. 09, 2002); U.S. Pat. No. 6,214,251 (Polymer electrolyte composition, Apr. 10, 2001); U.S. Pat. No. 5,998,559 (Single-ion conducting solid polymer electrolytes, and conductive compositions and batteries made therefrom; Dec. 07, 1999); U.S. Pat. No. 5,874,184 (Solid polymer electrolyte, battery and solid-state electric double layer capacitor using the same as well as processes for the manufacture thereof, Feb. 23, 1999); U.S. Pat. No. 5,698,664 (Synthesis of polyphosphazenes with controlled molecular weight and polydispersity, Dec. 16, 1997); U.S. Pat. No. 5,665,490 (Solid polymer electrolyte, battery and solid-state electric double layer capacitor using the same as well as processes for the manufacture thereof, Sep. 09, 1997); U.S. Pat. No. 5,633,098 (Batteries containing single-ion conducting solid polymer electrolytes, May 27, 1997); U.S. Pat No. 5,597,661 (Solid polymer electrolyte, battery and solid-state electric double layer capacitor using the same as well as processes for the manufacture thereof, Jan. 28, 1997); U.S. Pat. No. 5,567,783 (Polyphosphazenes bearing crown ether and related pod and side groups as solid solvents for ionic conduction, Oct. 22, 1996); U.S. Pat. No. 5,562,909 (Phosphazene polyelectrolytes as immunoadjuvants, Oct. 08, 1996); U.S. Pat. No. 5,548,060 (Sulfonation of polyphosphazenes, Aug. 20, 1996); U.S. Pat. No. 5,414,025 (Method of crosslinking of solid state battery electrolytes by ultraviolet radiation, May 09, 1995); U.S. Pat. No. 5,376,478 (Lithium secondary battery of vanadium pentoxide and polyphosphazenes, Dec. 27, 1994); U.S. Pat. No. 5,219,679 (Solid electrolytes, Jun. 15, 1993); 5,110,694 (Secondary Li battery incorporating 12-Crown-4 ether, May 05, 1992); U.S. Pat. No. 5,102,751 (Plasticizers useful for enhancing ionic conductivity of solid polymer electrolytes, Apr. 07, 1992); U.S. Pat. No. 5,061,581 (Novel solid polymer electrolytes, Oct. 29, 1991); U.S. Pat. No. 4,656,246 (Polyetheroxy-substituted polyphosphazene purification, Apr. 07, 1987); and U.S. Pat. No. 4,523,009, (Polyphosphazene compounds and method of preparation, Jun. 11, 1985), which are all incorporated herein by reference. Each discuss polyphosphazene polymers and/or other polymer electrolytes and/or lithium salts and combinations thereof
U.S. patent application Ser. No. 10/895,445 entitled “LITHIUM/AIR BATTERIES WITH LiPON AS SEPARATOR AND PROTECTIVE BARRIER AND METHOD” by the inventor of the present application (which is incorporated herein by reference) describes a method for making lithium batteries including depositing LiPON on a conductive substrate (e.g., a metal such as copper or aluminum) by depositing a chromium adhesion layer on an electrically insulating layer of silicon oxide by vacuum sputter deposition of 50 nm of chromium followed by 500 nm of copper. In some embodiments, a thin film of LiPON (Lithium Phosphorous OxyNitride) is then formed by low-pressure (<10 mtorr) sputter deposition of lithium orthophosphate (Li3PO4) in nitrogen. In some embodiments of the Li-air battery cells, LiPON was deposited over the copper anode current-collector contact to a thickness of 2.5 microns, and a layer of lithium metal was formed onto the copper anode current-collector contact by electroplating through the LiPON layer in a propylene carbonate/LiPF6 electrolyte solution. In some embodiments, the air cathode was a carbon-powder/polyfluoroacrylate-binder coating (Novec-1700) saturated with a propylene carbonate/LiPF6 organic electrolyte solution. In other embodiments, a cathode-current-collector contact layer having carbon granules is deposited, such that atmospheric oxygen could operate as the cathode reactant. This configuration requires providing air access to substantially the entire cathode surface, limiting the ability to densely stack layers for higher electrical capacity (i.e., amp-hours).
There is a need for rechargeable lithium-based batteries having improved protection against dendrite formation and with improved density, electrical capacity, rechargeability, and reliability, and smaller volume and lowered cost.